CCSS.Math.Content.HSS.MD.A.2

A random variable X has a mean of 5 and a st. dev of 0.40. A random variable Y has a mean of 8 and a st. dev of 0.60. If both are independent, what is the mean of X + Y?

• 13
• 6.5
• 14
• Not here.

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CCSS.Math.Content.HSS.MD.A.2

A September 2011 Gallup survey suggests that 38% of Americans are planning on voting for Barack Obama in the 2012 presidential election. Among a random sample of 100 people, approximately how many would you expect to vote for Obama? 

• 38 people
• 42 people
• 6 people
• Cannot be determined

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CCSS.Math.Content.HSS.MD.A.2

Suppose you pay $1.00 to roll a fair die with the understanding you will get $3.00 back rolling a 4 or a 2, and nothing otherwise.  What is the expected amount you win?

• $0.00
• -$1.00
• $1.00
• $3.00

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CCSS.Math.Content.HSS.MD.A.2

Given the probability model in the table below, what is the expected value of the random variable?
  X        50          20        5
P(X)     0.1         0.3      0.6

• 14
• 4.67
• 5
• 7.5

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CCSS.Math.Content.HSS.MD.A.2

If I flip a coin 10 times, how many times should I get heads?

• 1
• 10
• 3
• 5

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CCSS.Math.Content.HSS.MD.A.2

In a certain community, 30% of households have 1 child, 43% have 2 children, and 27% have 3 children. If a household is selected at random, what is the expected number of children in that household? HINT: A Probability table may be helpful.

• 2.00
• 2.13
• 1.97
• 1.27

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CCSS.Math.Content.HSS.MD.A.2

Which option gives the greatest Return on Investment?

• Option I
• Option II
• Option III
• It doesn't make a difference

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CCSS.Math.Content.HSS.MD.A.2

HINT: Read carefully! And think about the TOTAL amount of money being gained or lost in each situation!

• $275
• $625
• $2,750
• $6,250

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CCSS.Math.Content.HSS.MD.A.2

A line up for tickets to a local concert had an average (mean) waiting time of 20 minutes with a standard deviation of 4 minutes. If 2000 ticket buyers were in line, how many of them would expect to wait for less than 16 minutes?

• 320

• 1550

• 100

• 30

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CCSS.Math.Content.HSS.MD.A.2

CCSS.Math.Content.HSS.ID.A.4

The table represents the probability of guessing correct on a 5 question true-false quiz. Find the mean and the standard deviation.

• μ = .4; σ = 7.5

• μ = 2.5; σ = 1.1

• μ = 3; σ = 1.3

• μ = .1; σ = 0

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CCSS.Math.Content.HSS.MD.A.2